Systems and methods for rgb video coding enhancement

Abstract

Systems, methods, and devices are disclosed for performing adaptive residue color space conversion. A video bitstream may be received and a first flag may be determined based on the video bitstream. A residual may also be generated based on the video bitstream. The residual may be converted from a first color space to a second color space in response to the first flag.

What is claimed is: 
     
         1 . A method for decoding video content, the method comprising:
 receiving a video bitstream;   determining a first flag based on the video bitstream;   generating a residual based on the video bitstream;   determining to convert the residual from a first color space to a second color space based on the first flag; and   converting the residual from the first color space to the second color space.   
     
     
         2 . The method of  claim 1 , wherein determining the first flag comprises receiving the first flag at a coding unit level, and wherein the first flag is associated with a coding unit. 
     
     
         3 . The method of  claim 2 , wherein the first flag is received only when a second flag at the coding unit level indicates there is at least one residual with a non-zero value in the coding unit. 
     
     
         4 . The method of  claim 1 , wherein converting the residual from the first color space to the second color space comprises applying a color space conversion matrix. 
     
     
         5 . The method of  claim 4 , wherein the color space conversion matrix corresponds to one of an irreversible YCgCo to RGB conversion matrix or a reversible YCgCo to RGB conversion matrix. 
     
     
         6 . The method of  claim 5 , wherein:
 where the color space conversion matrix corresponds to the irreversible YCgCo to RGB conversion matrix, the irreversible YCgCo to RGB conversion matrix is applied in lossy coding, and   where the color space conversion matrix corresponds to the reversible YCgCo to RGB conversion matrix, the reversible YCgCo to RGB conversion matrix is applied in lossless coding.   
     
     
         7 . The method of  claim 4 , wherein converting the residual from the first color space to the second color space further comprises applying a matrix of scale factors. 
     
     
         8 . The method of  claim 7 , wherein the color space conversion matrix is not normalized, and wherein each row of the matrix of scale factors comprises scale factors corresponding to a norm of a corresponding row of the non-normalized color space conversion matrix. 
     
     
         9 . The method of  claim 4 , wherein the color space conversion matrix comprises at least one fixed-point precision coefficient. 
     
     
         10 . The method of  claim 1 , further comprising determining a second flag based on the video bitstream, wherein the second flag is signaled at one of a sequence level, a picture level, or a slice level, and wherein the second flag indicates whether a process of converting the residual from the first color space to the second color space is enabled for the sequence level, picture level, or slice level, respectively. 
     
     
         11 . A wireless transmit/receive unit (WTRU) comprising:
 a receiver configured to receive a video bitstream; and   a processor configured to:
 determine a first flag based on the video bitstream; 
 generate a residual based on the video bitstream; 
 determine to convert the residual from a first color space to a second color space based on the first flag; and 
 convert the residual from the first color space to the second color space. 
   
     
     
         12 . The WTRU of  claim 11 , wherein the receiver is further configured to receive the first flag at a coding unit level, and wherein the first flag is associated with a coding unit. 
     
     
         13 . The WTRU of  claim 12 , wherein the receiver is further configured to receive the first flag only when a second flag at the coding unit level indicates there is at least one residual with a non-zero value in the coding unit. 
     
     
         14 . The WTRU of  claim 11 , wherein the processor is configured to convert the residual from the first color space to the second color space by applying a color space conversion matrix. 
     
     
         15 . The WTRU of  claim 14 , wherein the color space conversion matrix corresponds to one of an irreversible YCgCo to RGB conversion matrix or a reversible YCgCo to RGB conversion matrix. 
     
     
         16 . The WTRU of  claim 15 , wherein:
 where the color space conversion matrix corresponds to the irreversible YCgCo to RGB conversion matrix, the irreversible YCgCo to RGB conversion matrix is applied in lossy coding, and   where the color space conversion matrix corresponds to the reversible YCgCo to RGB conversion matrix, the reversible YCgCo to RGB conversion matrix is applied in lossless coding.   
     
     
         17 . The WTRU of  claim 14 , wherein the processor is further configured to convert the residual from the first color space to the second color space by applying a matrix of scale factors. 
     
     
         18 . The WTRU of  claim 17 , wherein the color space conversion matrix is not normalized, and wherein each row of the matrix of scale factors comprises scale factors corresponding to a norm of a corresponding row of the non-normalized color space conversion matrix. 
     
     
         19 . The WTRU of  claim 14 , wherein the color space conversion matrix comprises at least one fixed-point precision coefficient. 
     
     
         20 . The WTRU of  claim 11 , wherein the processor is further configured to determine a second flag based on the video bitstream, wherein the second flag is signaled at one of a sequence level, a picture level, or a slice level, and wherein the second flag indicates whether a process of converting the residual from the first color space to the second color space is enabled for the sequence level, picture level, or slice level, respectively.